A brief discussion about coal

1. A Presentation on

2. Topics
 Wood
 WoodCharcoal
 Peat
 Coals’ Origin
Composition
Characteristics
significanceof its constituents

3. Wood
 A domestic fuel
 Used in tropical countries
 Basically cellulose &
lignin

4. Features of Wood
 Easy ignition
 Low ASH content (<1%)
 Burns with long non-smoky flame
 Low calorific value (4000-5000)
------Because of high O2 content(45%)
 Produce Wood Charcoal & Producer Gas

5. Charcoal
A bit Superior fuel than Wood
Found from wood carbonisation

6. Carbonisation
Heating in absence of air
Moisture Removed
Volatile matters Reduces
 Produces CHARCOAL
 Byproducts are Wood gas,tar etc
As a result:

7. Features of Charcoal
 High calorific value (7500-8000 kcal/kg)
 High specific surface area
 Poor mechanical strength
 Raw material for CS2
 Used for removing obnoxious and colouring
materials

8. Peat
First stage of coal formation
from wood
Most immature coal
or
Originates from Vegetable matter

9. Features of peat
 Friable
 Composition & property varies place to place
 Moderate calorific value
 Low furnace temperature & efficiency
 Used for fertilizer and power generation

10. Coal

11. Coal
 Combustible black or brownish black sedimentary rock
 Occurs in the earth’s crust
 Formed by partial decay of plant materials
 A runtime of several million years
 Driven by bacteria,temperature and pressure

12. Origin & Formation of coal
 Burial
 Pressure
 Heat
 Time
Bacterial
decay

13. Formation of coal
Geological aspects
In situtheory
Drift theory

14. Formation of coal
Peat Lignite Brown-coal Sub-Bituminus Bituminus
Semi-anthracite
Anthracite
Graphite

15. Rank of coal
Peat Lignite Bituminus Anthracite
Moisture content decreases
Volatile matter decreases
Carbon content increases
Calorific value increases
Hardness increases

16. Peat
 Starting point of coal formation
 High moisture content
 Carbon : 60-64%
 Oxygen : 35-30%
 Coparatively low CV
 Light brown colour

17. Lignite
 Second stage of coal formation
 Moisture up to 60%
 Carbon : 60-75%
 Oxygen : 30-20%
 Brown appearance
 CV of 5000 kcal/kg

18. Sub-Bituminus
 Low moisture content
 Carbon : 70-80%
 Oxygen : 10-20%
 Black and Smooth
 CV of 7000 kcal/kg
 No caking power

19. Bituminus
 Low moisture content (<10%)
 Carbon : 75-90%
 Oxygen : 5-10%
 Black and Brittle
 CV of 9000 kcak/kg

20. Semi anthracite
 Harder than bituminous coal
 Carbon : 90-93%
 Oxygen : 1-4%
 Also known as Steam coal
 CV of 8600 kcal/kg

21. Anthracite
 Highest rank of coal
 Very low moisture content
 Carbon : 93+%
 Oxygen : 1-2%
 Harder,glossy and black
 Zero caking power
 CV of 8000-8500 kcal/kg

22. Graphite
 Technically the highest rank
 Difficult to ignite
 Not used as fuel

23. Unusual Coals
 Found Rarely
 High H2 content
 Does not fall in any category
Channelcoal :

24. Unusual Coals
 Also known as boghead coal
 Rich in parafin oil
 Does not fall in any category
Torbanites :

25. Analysis of Coal
Proximateanalysis
Ultimate analysis
Heating/Calorific value

26. Proximate analysis
1. Moisture content
2. Volatile matter
3. Ash content
4. Fixed carbon
Parametes :

27. Ultimate Analysis
Parameters :
1. Carbon
2. Hydrogen
3. Oxygen
4. Sulphur
5. Nitrogens
6. Chlorine
 Mercury

28. Effects of the componants
Moisture :
 Reduces Calorific value
 Increase coal consumption for heating purpose
 Lengthens time for heating
 Aids radiation heat transfer

29. Effects of the componants
Volatile matter :
 Lowers ignition temperature
 Reduces calorific value
 Increase quantity of coke oven gas
 Sets minimum limit on furnace size

30. Effects of the componants
Ash content :
 Reduces calorific value
 Reduces burning capacity
 Causes Clinkering an Slagging

31. Effects of the componants
Fixed Carbon :
 Increases the Calorific value with constant
proportionality

32. Effects of the componants
Hydrogen :
 Increases the Calorific value

33. Effects of the componants
Oxygen :
 Reduces the Calorific value
 Reduces Caking power

34. Effects of the componants
Nitrogen :
 Reduces the Calorific value

35. Effects of the componants
Sulphur :
 Increases Calorific Value
 Creates corrosive environment
 Causes HOT-SHORTNESS
 Limits exit flue gas temperature

36. Effects of the componants
Chlorine :
 Reduces fusion points of ash in coal

37. Effects of the componants
Phosphorus :
 Creates COLD-SHOTNESS in steelmaking

38. Uses of Coal
85% for electrical power generation.
15% for manufacturing as Coke.

39. References
• Elements of Fuels, Furnaces & Refractories
-By O.P. Gupta
• http://f03.classes.colgate.edu/fsem037-
coal/Coal/Default/composition_of_coal.htm
• https://www.worldcoal.org/coal
• https://www.uky.edu/KGS/coal/coalform.htm
• http://www.coaleducation.org/q&a/how_coal_formed.htm

40. Presented by :
Nabila Ali (1311035)
Shimul Chandra Das (1311034)
Mehedi Mehetab Shihab (1311029)